NCT07593677

Brief Summary

The goal of this clinical trial is to compare the effect of different types of text messages on physical activity levels of middle-aged and older adults and to determine whether these messages are effective in adults age 40 and older who are engaging in less than 90 minutes per week of moderate or higher intensity physical activity. The main questions it aims to answer are:

  • Which types of motivational messages show the greatest effects on changes in daily step counts in a 3-month precision text messaging intervention?
  • What are the effects of personalized text messages on automatic affective evaluations, habit strength (experienced automaticity), exercise identity, working memory capacity, and processing speed? Participants will:
  • Wear a Fitbit activity tracker continuously for 3 months and are encouraged to continue wearing it through 6 months.
  • Wear an activPAL activity monitor on their thigh for 7-day assessment periods at the beginning of the study, at 3 months, and at 6 months.
  • Complete 3 cognitive assessments ("brain games") per day on their smartphone during the 7-day assessment periods at baseline, 3 months, and 6 months.
  • Be asked to set goals to increase their daily steps over the first 3 months of the study.
  • Receive up to 4 motivational text messages per day for 3 months to encourage physical activity.
  • Keep study-related apps (Fitbit app, AIM app, MetricWire app) open in the background on their smartphone.
  • Complete questionnaires at the beginning of the study, at 3 months, and at 6 months

Trial Health

63
Monitor

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
150

participants targeted

Target at P75+ for not_applicable

Timeline
14mo left

Started Jun 2026

Geographic Reach
1 country

1 active site

Status
not yet recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

May 4, 2026

Completed
14 days until next milestone

First Posted

Study publicly available on registry

May 18, 2026

Completed
14 days until next milestone

Study Start

First participant enrolled

June 1, 2026

Expected
11 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 3, 2027

3 months until next milestone

Study Completion

Last participant's last visit for all outcomes

August 2, 2027

Last Updated

May 22, 2026

Status Verified

May 1, 2026

Enrollment Period

11 months

First QC Date

May 4, 2026

Last Update Submit

May 21, 2026

Conditions

Keywords

physical activitybehavioral adherencemotivationcognitive functionagingolder adultstext messaging

Outcome Measures

Primary Outcomes (1)

  • Daily Step Count

    The primary outcome measure is the average daily step count, which is assessed using a blinded, research-grade activPAL activity monitor, worn on the thigh for a 7-day assessment period.

    The activPAL is worn on the thigh for a 7-day assessment period before the intervention begins (baseline), after 3 months of intervention, and then again 3 months after the intervention is complete. The total time frame is 6 months.

Secondary Outcomes (5)

  • Mechanisms of Behavior Change for Adherence: Habit Strength

    These secondary outcomes are collected at the same major time points as the primary outcome: baseline (month 0), post-intervention (month 3), and follow-up (month 6).

  • Mechanisms of Behavior Change for Adherence: Exercise Identity (Reflective)

    These secondary outcomes are collected at the same major time points as the primary outcome: baseline (month 0), post-intervention (month 3), and follow-up (month 6).

  • Mechanisms of Behavior Change for Adherence: Automatic Affective Evaluations

    These secondary outcomes are collected at the same major time points as the primary outcome: baseline (month 0), post-intervention (month 3), and follow-up (month 6).

  • Ambulatory Cognitive Function: Processing Speed

    These secondary outcomes are collected at the same major time points as the primary outcome: Baseline (month 0), post-intervention (month 3), and follow-up (6 month).

  • Ambulatory Cognitive Function: Working Memory Capacity

    These secondary outcomes are collected at the same major time points as the primary outcome: Baseline (month 0), post-intervention (month 3), and follow-up (6 month).

Study Arms (2)

Validated library of text messages

ACTIVE COMPARATOR

Participants in this arm will receive motivational text messages that have been written and used in previous studies.

Behavioral: Text Messaging Intervention

Newly created text messages

EXPERIMENTAL

Participants in this arm will receive motivational text messages that have not been used in previous studies.

Behavioral: Text Messaging Intervention

Interventions

Participants will receive up to 4 motivational text messages per day during a self-selected 12-hour window. These messages focus on two content areas: 1) Move more, and 2) sit less. Delivery of these messages occurs in two phases: 1. Random AIM (month 1): Messages are sent at random times within the participant's window to collect baseline data on their behavioral responses. 2. Precision AIM (months 2 and 3): Messages are sent at optimized times based on person-specific models that are created from the individual's previous responses to text messages from month 1.

Newly created text messagesValidated library of text messages

Eligibility Criteria

Age40 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Be 40 years of age or older
  • Own a smartphone running an Android or iOS operating system
  • Have proficiency with the English language
  • Be capable of providing informed consent
  • Be able to perform moderate physical activity without restrictions
  • Be willing to complete the entire 6-month protocol
  • Be willing to establish a 12-hour window - beginning no later than 9:45 am and ending no later than 9:45 pm - for receiving text messages.

You may not qualify if:

  • Residing outside of the continental United States
  • Self-reporting 90 minutes or more of moderate-to-vigorous intensity physical activity per week
  • contraindications to normal physical activity as identified on the Physical Activity Readiness Questionnaire (PAR-Q)
  • Mobility restrictions that interfere with unassisted physical activity
  • Being pregnant or planning to become pregnant during the study
  • Planning to undergo surgery during the course of the study protocol
  • Having a prior diagnosis of Alzheimer's disease or a related dementia
  • Evidence of mild cognitive impairment as indicated by a mini-Montreal Cognitive Assessment (MoCA) test score of 12 or higher
  • Concurrent participation in another study involving weight loss or physical activity
  • Failure to respond to at least 85% of Ecological Momentary Assessment (EMA) prompts during the 7-day qualification phase.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

University of Michigan

Ann Arbor, Michigan, 48109, United States

Location

MeSH Terms

Conditions

Sedentary BehaviorMotor Activity

Condition Hierarchy (Ancestors)

Behavior

Study Officials

  • David E Conroy, PhD

    University of Michigan

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Ann M Mehringer

CONTACT

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
OTHER
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Bickner Chair of Kinesiology and Professor of Kinesiology, School of Kinesiology

Study Record Dates

First Submitted

May 4, 2026

First Posted

May 18, 2026

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

May 3, 2027

Study Completion (Estimated)

August 2, 2027

Last Updated

May 22, 2026

Record last verified: 2026-05

Data Sharing

IPD Sharing
Will share

De-identified individual participant data (IPD) underlying the results reported in primary and secondary publications will be shared. This includes baseline behavioral metrics, coarsened demographics, post-intervention outcomes, and follow-up data. To protect participant privacy, all data will be stripped of direct identifiers, ages will be binned into 5-to-10-year bands, geographic markers restricted to broad regions, and timeline dates converted to "days since randomization." Raw, free-text qualitative journal entries will be suppressed entirely due to re-identification risks.

Shared Documents
STUDY PROTOCOL, SAP, ICF
Time Frame
Data and supporting documentation will be made available concurrently with the primary peer-reviewed publication of the trial results and will remain accessible for 5 years post-publication. This immediate availability complies with the NIH Data Management and Sharing Policy.
Access Criteria
Access is restricted to qualified external researchers affiliated with an accredited academic or non-profit research institution. Applicants must submit a formal, written research proposal detailing a sound scientific hypothesis and an analytical plan, alongside documentation of local IRB approval/waiver. Approved requestors and their sponsoring institutions must sign a legally binding Data Use Agreement (DUA) that strictly prohibits any re-identification or external data-linking attempts.
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